The present invention relates generally to protection against rhinovirus infection. While the invention is subject to a wide range of applications, it is especially suited for vaccination of animals and humans against human rhinovirus infection and the prevention of associated illnesses. In addition, the invention provides methods of identifying and testing vaccines and therapeutics for the prevention and amelioration of human rhinovirus infection and associated illnesses and, thereby, provides methods of determining the efficacy of vaccines and therapeutics against human rhinovirus.
Human rhinoviruses (HRV) represent the single most important etiological agents of the common cold and the most frequent cause of acute respiratory infection in humans (Arruda et al., J. Clin. Microbiol. 35:2864, 1997; Turner and Couch, Rhinoviruses, Vol. 1, Lippincott-Williams & Wilkins, Philadelphia, Pa., 2007). HRV are single-stranded RNA viruses members of the Picornaviridae family, genus enterovirus, which also include polioviruses and coxsackieviruses. The increasing use of molecular methods for respiratory virus detection and characterization has contributed to cluster the HRV prototype strains into three genetic species: HRV-A, HRV-B (Savolainen et al., J. Gen. Virol. 83:333, 2002), and the recently identified HRV-C (Simmonds et al., J. Gen. Virol. 91:2409, 2013). HRV-A and HRV-B comprise a number of antigenically distinct viruses designated on the basis of their cross-neutralization properties in vitro, and currently totaling 75 serotypes of HRV-A and 25 serotypes of HRV-B (Hamparian et al., Virology 159:191, 1987; Kapikian et al., Nature 213:761, 1967; Ledford et al., J. Virol. 78:3663, 2004). Viruses corresponding to the HRV-C species do not grow in standard cell culture (for example, HeLa or embryonic fibroblasts) but are now known to be highly prevalent and widely circulating worldwide.
HRV16 belongs to the species HRV-A also known as the major group. HRV16 uses the well-characterized intercellular adhesion molecule-1 (ICAM-1) receptor for attachment and entry (Lee et al., Virus Genes 9:177, 1995), and has been a model virus for studying transmission of rhinoviruses (D'Alessio et al., J. Infect. Dis. 133:28, 1976), pathogenesis of the common cold (Bush et al., J. Allergy Clin. Immunol. 61:80, 1978), virus-induced asthma and chronic obstructive pulmonary disease (COPD) (Malia et al., Respir. Res. 7:116, 2006; Bossios et al., Clin. Exp. Allergy 38:1615, 2008; Sykes et al., J. Allergy Clin. Immunol. 129:1506, 2012), and evaluation of anti-rhinovirus drugs in human volunteers because it reproducibly induces strong symptoms in human subjects. Currently, HRV16 is also widely used for in vitro studies aiming to define the molecular mechanisms by which rhinovirus infection of respiratory epithelial cell triggers the overwhelming inflammation in airways (Korpi-Steiner et al., J. Leukoc. Biol. 80:1364, 2006; Korpi-Steiner et al, Clin. Exp. Allergy 40:1203, 2008).
Until now, three different cell-surface receptors have been shown to be used by rhinoviruses. Rhinovirus type 87 appears to use the decay-accelerating receptor factor as a receptor (Blomqvist et al., J. Clin. Microbiol. 40:4218, 2002). The minor group receptor, low-density lipoprotein (LDL), is used by at least ten serotypes (1A, 1B, 2, 29, 30, 31, 44, 47, 49, and 62), and the ICAM-1 receptor is used by the remaining described serotypes of the major group including HRV16.
HRV infection is typically responsible for upper respiratory symptoms including rhinorrhea, sore throat, nasal congestion, sneezing, cough, and headache. More importantly, HRV has emerged as the most frequent pathogen associated with exacerbation episodes in asthmatic (Holgate, J. Allergy Clin. Immunol. 118:587, 2006) and COPD patients (Seemungal et al., Eur. Respir. J. 16:677, 2000). Several avenues have been followed towards the development of preventive and therapeutic strategies against HRV infections. However, due to the occurrence of more than 100 HRV serotypes with high sequence variability in the antigenic sites, no rhinovirus vaccine and no HRV-specific antiviral drug are currently available. Furthermore, although it is clear that animal models to test the efficacy of HRV vaccination or therapy in vivo would be important assets, most efforts to develop such resources have resulted in mouse models of limited value.
A major characteristic of HRV is their high host species specificity attributable, for the major group viruses, primarily to the use of ICAM-1 as a receptor. Chimpanzees have been successfully infected with HRV14 and 43, and gibbons with HRV1A, 2 and 14, but no overt illness was observed in the infected animals (Pinto and Haff, Nature 224:1310, 1969; Dick, Proc. Soc. Exp. Biol. Med. 127:1079, 1968). Infection was not demonstrated in rabbits, guinea pigs, weanling mice, or 1-day-old mice infected with HRV by the subcutaneous, intraperitoneal, or intravenous routes. Similarly, intracranial injections into monkeys, hamsters, or baby mice did not result in either infection or disease (Hamparian et al., Proc. Soc. Exp. Biol. Med. 108:444, 1961; Kisch et al., Am. J. Hyg. 79:125, 1964). Intranasal inoculation of ferrets, hamsters, and baby mice was also investigated without effects. HRV2 was adapted to grow in L cells and used in mice, but limited replication was demonstrated (Yin and Lomax, J. Gen. Virol. 67:2335, 1986). The BALB/c mouse was proposed recently as a model for rhinovirus-induced disease and exacerbation of allergic airway inflammation (Bartlett et al., Nat. Med. 14:199, 2008). Using HRV1B, it was demonstrated that infection is localized in the lungs, induces airway and pulmonary inflammation, and mucin production despite low viral replication. In addition, a model for HRV16 pathogenesis was presented using transgenic mice expressing a human/mouse ICAM-1 chimeric receptor (Bartlett et al., Nat. Med. 14:199, 2008). This model showed low levels of viral replication similar to HRV in BALB/c mice. Virus replication in the upper respiratory tract (URT) was not analyzed in either model. Balb/c mice were also recently used for testing antiviral drugs against HRV2 (Falah et al., J. Virol. 86:691, 2012). To date, no human rhinovirus vaccination/challenge/protection studies have been performed and validated in any animal model. Thus, the feasibility of preclinical studies in animal models for testing the efficacy of anti-rhinovirus vaccines and therapeutics has been severely hampered.
The morbidity and mortality attributable to rhinovirus infection is considerable and results in billions of dollars of health care cost every year. Despite the significance of the problem, no effective prevention of HRV infection or treatment of HRV-associated disease is currently available. Attempts to develop a small animal model of HRV infection in many species have failed, thus severely hampering mechanistic studies and the development of vaccines and therapeutics against HRV infection. Over the years, the cotton rat (Sigmodon hispidus) has been shown to support replication of a broad spectrum of human viruses including respiratory syncytial virus (RSV) (Prince et al., Am. J. Pathol. 93:771, 1978), non-adapted strains of human and avian influenza (Blanco et al., J. Virol. 87:2036, 2013; Ottolini et al., Pediatr. Pulmonol. 36:290, 2003; Ottolini et al., J. Gen. Virol. 86:2823, 2005), measles (Pfeuffer et al., J. Virol. 77:150, 2003; Wyde et al., Proc. Soc. Exp. Biol. Med. 201:80, 1992), several adenovirus serotypes (Pacini et al., J. Infect. Dis. 150:92, 1984; Prince et al., J. Virol. 67:101, 1993; Tsai et al., Arch. Ophthalmol. 110:1167, 1992), parainfluenza virus type 3 (Porter et al., J. Virol. 65:103, 1991), and human metapneumovirus (Wyde et al., Antiviral Res. 66:57, 2005) (Hamelin et al., J. Gen. Virol. 88:3391, 2007; Williams et al., J. Virol. 79:10944, 2005). The cotton rat is well-recognized for its pivotal role in the development of the only effective prophylactic treatments against RSV disease (RespiGam® and Synagis®). However, to date, there is no report that the cotton rat can support the replication of HRV.
There is no vaccine against human rhinovirus, and there is no specific therapy against human rhinovirus infection and associated illnesses. Thus, there remains a need for safe and effective approaches to protect animals and humans against human rhinoviruses. In particular, there remains a need for specific vaccines to prevent human rhinovirus infection, and for therapeutics to ameliorate myriad illnesses associated with rhinovirus infection. In addition, there remains an unfulfilled need for experimental methods and approaches for identifying (and determining the efficacy of) vaccines and therapeutic agents against human rhinovirus.